Sep 9, 2009
Why mp3s suck, and how to hear it
I hate mp3, and this post will tell you why.
DO NOT read this post if you have a large collection of mp3s, enjoy listening to them and can’t hear any problems with them, because it’ll ruin them for you !
There’s been plenty written on how mp3 works, and why lossy compression sounds worse than uncompressed audio in general. My aim here is to demonstrate how mp3 sounds bad, for all the people who keep telling me there’s no difference.
I’m going to give you clear guidelines and examples on what to listen for and the negative effects of mp3, but there’s no going back – once you can hear the problems, you’ll never stop hearing them.
This isn’t limited to audiophiles, or “golden ears”, by the way – in my opinion anyone can hear this stuff, with a few pointers.
So seriously, unless you’re prepared to start using Ogg Vorbis, FLAC or AAC - stop reading now !
Still here ? Good.
First, I need to make this clear – I have nothing against lossy audio or data compression in itself – I do most of my casual listening on an iPod, using 128kbps AAC files – they sound fine. Not as good as the original CDs, obviously, but OK. And yes, I’m well aware that AAC is just a more advanced version of mp3. But the fact is that mp3 has fundamental limitations – even at higher bitrates.
Next – I’m also a pragmatist. mp3 is a temporary phenomenon, just like AM radio, cassettes and CDs. In the long run, none of those have killed music, and neither will mp3, or lossy compression in general. So, why the rant ?
Because people keep saying mp3 sounds great, or “indistinguishable from CD” and it’s just not true.
mp3 isn’t good enough
It doesn’t matter what encoder you use, it doesn’t matter what settings you use or what pre-processing you apply – mp3 just doesn’t cut it. AAC and later, more sophisticated encoders use more advanced encoding methods, and sound better to varying degrees, but mp3 just FAILs.
How does it fail ? That depends a little on the encoder being used, but some of my own pet hates include:
- mp3 sizzle – the artificial, unnatural swirling metallic noises that sound like someone’s added chime bars to everything, or there’s a mosquito buzzing in your ear. Some people actually say we prefer these noises in mp3s – I say bullshizzle !
- Added distortion – Yet another side effect of the so-called Loudness Wars. mp3 encoders rarely include any headroom for the encoding process itself, so the added processing pushes the music even further over the limits, generating inter-sample peaks and adding even more distortion in the process
- Flat, two-dimensional sound mp3 works by throwing away musical information that we supposedly can’t hear – up to 90% of the original information, at 128kbps. That means all the subtle, delicate stuff, like ambience, space and realism. So a lush, three-dimension original is reduced to a flat, cardboard replica of itself
- Mushiness All but the very best mp3 encodes just sound fuzzy, muddled and – well, mushy !
Hear for yourself
Don’t take my word for it – here are some examples. First, a truly nasty 128kbps mp3 example, from a Deep Purple live album I mixed a while back:
Please install Flash plugin
(Before anyone jumps on me, I’ve heard even a 256 kbps mp3s sounding like this – I’ve just used a low quality version to make the point.)
If that doesn’t sound too bad to you at first, try this - I’ve filtered the file to highlight the high frequencies. You can hear the problems most clearly when the vocals start:
Please install Flash plugin
Some people describe this effect as “sizzle”, or “swirlies”. It’s not just that I’ve removed all the bass, what I’m pointing out is the unatural bubbling, twinkling “chime-bar” type sound, or as my friend and fellow mastering engineer Nick Watson once called it, the “flocks of tweeting ultrasonic birdies”. It also reminds me of someone crinkling up tin foil !
Once you’ve picked it out, listen the first version again. Doesn’t sound so nice now, does it ? Can you ignore the swirlies, now you know they are there ?
Now download and listen to the original file:
‘Talk About Love – Excerpt’ – 5 MB WAV file
Listen to the clarity, punch, and bite of the WAV, compared to the swirly, soggy mess of an mp3. Which one do you prefer ?
The loss of depth, richness and three-dimensionality is more subtle side-effect, but just as unfortunate. Here’s a snippet of a recording I did for the brilliant Hans Koller, featuring Christine Tobin on vocals:
Please install Flash plugin
(This is a much better mp3 encode, with far fewer heinous swirlies. But still…)
Here’s the WAV version:
‘The Great Bear And The Small – Excerpt’ – 11 MB WAV File
Don’t expect the difference here to leap out at you straight away, it’s more a case of feeling it – listen to the swirls of the harp from 30 seconds in, listen to the piano and Christine’s voice – on the wav file, there’s a warmth, and a depth, and a sparkle that in the mp3 has just gone.
Listen to the wav several times over, then switch to the mp3. Do you honestly feel it sounds as good ? The mp3 is OK, but it’s just… meh. I’m not drawn in, my attention wanders, it doesn’t move me.
Something essential has been lost, and you can’t get it back. And once you’ve heard that loss, even cranking the data-rate up doesn’t help. The only solution is a more advanced format, or lossless files.
Try listening to the mp3s in your music collection. Go back and compare them to the CDs you ripped them from.
…Sorry.
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Update: I’ve had lots of interest in this post, and lots of discussion, especially on link-sharing sites. There are a few common responses that I want to answer here.
No-one uses 128 kbps mp3s
Wrong. If you’ve made this comment, you probably already know about LAME and the all other flavours of mp3 codec, and you probably do choose to use higher bit-rates, but you’re in the minority. Most “regular listeners” go for the default settings – and even in iTunes this is only 160 kbps.
192/320 kbps sounds fine
Sometimes. This depends so heavily on the material, the encoder and the codec – you simply can’t make blanket assumptions. Ironically one of the factors that makes mp3 so popular – the fact that it’s free and open-source – also makes it far harder to get a decent encode. By contrast, the grip Apple have over the AAC format at least ensures consistently high standards of encoding.
You’re just an Apple fanboy
No. Well alright, yes – I am a big fan of Apple’s products, but there are plenty of other alternatives to mp3 – OGG Vorbis, FLAC etc. The only reason I mention AAC a lot is it’s a format I have deep experience of, and always sounded good (but not perfect !) to me.
And another thing
To everyone who keeps saying “just use 320 kbps”, I say – why ?!? mp3 simply has inherent limitations compared to other formats. The whole point of lossy audio is to save space. At 128 kbps that saving is 90% – well worth having. At 320 kbps though, that saving is only 60% and it still doesn’t sound great – I’d rather go with FLAC or Apple lossless, which can often achieve a 50% saving, and have something that sounds every bit as good as the source.
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Well iPod suggests portable listening and most people have lower demands for that than more “serious” forms of listening. It doesn’t have to be “true to the original” just “good enough to listen to”.
As for AAC it stays “good enough to listen to” for very low bitrates.
I think however that Ian’s problem with this isn’t what people listen privately to on their iPods or Sansas or whatever music player you use, it’s your choice what codec to encode with and at which bitrate. The problem is that music are being sold already encoded in MP3 formats which means that someone else already made the choice for you.
Not to kick up an old thread here, but AACs and OGGs aren’t that much better. That don’t really produce the sizzle, but they’re just as flat because they compress music the same way.
What I HATE about the MP3 format, is that starting during the `00s, and increasingly thus far throughout the “20-teens” era, Rock and Pop artists have “mixed” their music so as to still sound alright on the highly compressed and crappy MP3 format. ALL contemporary music these days just sounds “loud and blaring”; without anything akin to the dynamics and naunce that music USED to have, especially during the `70s, but also during the `80s, and 90s. Everyone, even Country and “soft Pop” artists, “mix” everything to sound LOUD. If a person plays such music at “normal” volume levels, it sound blaring; and if you play it at a lower level, it just sounds “dull”.
~ Personally, I can`t wait until the increasingly tiny and affordable “storage medium” revolution gives us iPod type devices with Gigabytes-worth of data storage space, so that common people can download large amounts of songs in WAV file, or Direct Stream Digital encoding format. THEN the artists can resume using dynamics in the recorded performances, like music SHOULD BE.(Anyone that may have any “inside information” on how or when this developement may be occuring, please do reply to this comment.)
Just to stir things up a bit. I am a musician with a home studio. I record music in wav format at 32 bits and 44100 Hz. I listen on studio monitors 1 meter away from my ears mounted on insulated stands in a room with sound absorption to reduce unwanted reflections. I spend hours finding exactly he sound I want.
But when I am not recording music I listen to my collection on mp3. I have ripped all my CDs to mp3 and chucked the originals. I carry a Creative Zen around with all my music on and I love it.
The important point here is how the mind and ears work together. I know all the records in my collection very well, I love them. So I don’t need perfect, or even very good, reproduction to enjoy them. I just need enough to remind me how they sound and the incredible instrument that is the brain fills in all the rest.
Sure I listen to new music in good quality, but once I know a song mp3 is plenty good enough for me!
Please kill me before AAC or ALAC become new mediums of sound. I prefer my music without blaring corporate watermarking from a terribly restrictive iTunes service, thank you very much.
But aside from that, I’ve shown these examples to a few friends in their mid thirties and fourties. All of them have been able to pick out these correctly, among other web-based tests, in a matter of four seconds with mid-range equipment. Even the MP3 – FLAC difference test is blaringly obvious to most of the people in question. I have no doubt that this is going to prove less successful with a younger crowd, even with their more dynamic reception of the frequency band.
For the Talk About Love example, the wav is also lacking in a rich sound stage and dynamic range — That’s much worse to me than the swirlies. I guess what I am challenging is — would better mixes come out more acceptably through the compression process, esp if they’re at >= 320 kbps?
Also, can swirlies be attentuated on decode?
Hi Ray,
More dynamic, open music often survives encoding better, because the encoder has to work “less hard”, and so has “more to work with”. However mp3 just don’t do as good a job as more advanced codecs – an AAC of that track can sound pretty good (and to be fair, you can get better mp3 encodes of it, too.)
Higher bit-rates almost always help, but really why bother, these days ?
I’m not aware of “swirly reduction” decoding, but such processing will always have further side-effects, like attempts to remove “mosquitos” from jpeg images, for example. At the end of the day, once the information is gone, it’s gone…
@ Matt – actually young people also prefer high-quality formats:
http://productionadvice.co.uk/listeners-can-hear/
I agree that mp3 is not the best format for compressed music however it is the only format that I know that works in both itunes and windows media player. I need a format that allows me to play music on my smart phone and my ipod touch and my computer easily without having to hunt down third party plugins and other forms of manipulation.
To my knowledge mp3 is not necessarily “free” and far from being open-source: https://en.wikipedia.org/wiki/MP3#Licensing_and_patent_issues
I listen to 320CBR for the time being. When media players support .flac or .ogg and when bigger flash memory becomes an option, I’ll make the switch.
Every mp3 has a tiny bit of silence at its beginning, resulting from the conversion process. Just listen to a live CD converted to mp3, you will always hear that gap on every track transition, which ruins the “live experience” for me if you know what I mean. People alway comlain that flac and the likes are inconvenient formats for their iPod/iPhones etc., in fact they just need a proper audio player software that supports the format, or get the right plugin or in the case of apple use apple lossless etc. most of the stuff is free and easily to find if you know how to make use of google.